Light-curable or light-hardenable materials are widely used in dentistry for the restoration of teeth, for example for filling a cavity in a tooth. Such materials typically can be made to provide optical characteristics that resemble those of natural teeth, which makes those materials a favored alternative to unpleasant looking amalgam materials, for example.
Light-hardenable materials often include a polymerizable matrix material and filler materials including colorants, and may initially be generally soft or flowable so that they can be applied in a desired location and shape. For example, for restoration of a tooth the dental material may be filled into a tooth cavity and shaped so that the restored tooth resembles a natural tooth. Once the desired shape has been formed, the material may be hardened by exposing it to light of a desired wavelength and for a certain material dependent time period. The light typically activates photoinitiators in the dental material that cause the matrix material to polymerize.
The use of dental materials that are hardenable by blue light of a wavelength of between about 450 and 500 nm has become common in dentistry. Accordingly, dental light irradiation devices used for hardening such dental materials typically emit light at such wavelengths and typically enable the device to automatically control the light emission for only a pre-selected or pre-selectable time period. Such dental light irradiation device, for example, is available from 3M ESPE, Germany, under the trade designation Elipar™ S10 LED Curing Light.
Normally irradiating a dental material causes that portion of the dental material to harden, which is exposed to sufficiently intense light emitted from the device. Therefore, appropriate irradiation of the dental material to be hardened is critical for the quality and durability of the hardened dental material.
Typically devices of the prior art can operate at different operation times and/or at different intensities to control appropriate hardening of the dental material. Thus too long or too short exposure of dental can typically be controlled. However there is still a need for a device which minimizes the dependency between quality of the filling and handling of the device. Further it is still desirable to provide a device that allows easy handling for appropriately hardening dental materials in different situations.